Sir Alex Ferguson's decision to reunite Paul Scholes and Michael Carrick as a central pair has its drawbacksThe opportunity for Manchester United to avenge Manchester City's 6-1 win at Old Trafford in October is the inevitable context for this match. In tactical terms, however, City's 1-0 FA Cup semi-final victory at Wembley last April is a more relevant previous encounter.Yaya Touré scored a winning goal that brilliantly epitomised the two teams' styles: the Ivorian stormed forward to intercept a short Michael Carrick pass intended for Paul Scholes, drove past the United defence, and finished past Edwin van der Sar. It was a fitting decider in a game primarily about tempo – United wanted to be slow and relaxed in possession with Carrick and Scholes, while City were about the power of Touré, Nigel de Jong and Gareth Barry....